The 27-year-old has spurned reported interest from several clubs across Europe in order to ply his trade with the Premier League newcomers.
The Frenchman is venturing out of his homeland for the first time, having spent his entire career at the Stade Chaban Delmas.
Palace will begin their first season back in the top flight since 2004-05 with a match against Tottenham on Sunday, with several of manager Ian Holloway's new signings likely to feature.
Marange's deal is still subject to approval from the Football Association and the Premier League, but he could be drafted in for a debut.
Holloway has already added the likes of Peterborough United striker Dwight Gayle and Arsenal forward Marouane Chamakh to his squad.
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The games Arsenal star Bukayo Saka is expected to miss following his painful injury setback
